Introducing LTC

⑴Hurry up! Does anyone know the encoding method and decoding method of LTC time code?

Time encoding

I. Concept

Here we will explain the media stream An important concept in processing – time encoding.

Time encoding is an auxiliary data for video and audio streams. It is contained in video and audio files, which we can understand as timestamps.

SMPTE timecode is the sum of a SMPTE time and control code, which is a continuous digital address frame, flags and additional data in a video and audio stream. It is defined in ANSI/SMPTE12-1986. Its purpose is to provide a computer-processable video and audio address.

The maximum SMPTE time code data structure is a 80-bit frame, which contains the following contents:

a, a hh::mm::ss::ff ( Timestamp in hour::minute::second::frame) format.

b. Eight 4-bit binary data are usually called “user bits”.

c, Different Flags

d, Sync Sequence

e, Verification Sum

This format is used in DirectShow is defined as TIMECODE_SAMPLE.

The time code is divided into two forms, one is the linear time format LTC (Longitudinal Coding), each time code represents a frame in continuous time. Another type of timecode is VITC (transverse coding), which stores two lines of the video signal in a vertical blanking interval, somewhere between 10 and 20.

LTC timecode is very easy to add to eg videotape because it is encoded as a separate audio signal. But it cannot be read while the tape drive is paused, slow-forwarded, or fast-forwarded. In addition, in non-professional video recorders, it may lose an audio signal.

VITC timecode is different from LTC in that it can be read at 0-15x speed. It can also read from video capture cards. But if it is to be recorded to tape, it may require some additional equipment, which is usually more expensive.

SMPTE time code supports two modes at the same time, one is non-drop frame mode and the other is drop frame mode. In non-drop frame mode, the timecode is recorded in continuous increments. It can complete real-time playback work up to 30 frames, or higher.

The video playback standard of the NTSC system is 29.97 frames per second, which is due to the compatibility of the monochrome TV system. This leads to a question. In the non-drop frame mode, there will be 108 frames out of sync in one hour, that is, when one hour is in real time, the time code is only read 00:59:56:12. When you calculate There are some issues with streaming playback time. In order to solve this problem, we can skip the frame implementation when it can be tolerated. This is achieved by skipping two frames at the start of each minute count but not skipping frames at 00, 20, 30, 40, and 50 minutes. Using this scheme, the error of our network test results is less than one frame per hour, and the error is about 3 frames per 24 hours.

In the actual work now, although both modes are provided at the same time, the frame-dropping mode is usually adopted by us.

Second, the typical application of time code

Controlling peripheral devices for video capture and editing is a typical application. Such applications need to identify each frame of video and audio frames, and the method they use is to use SMPTE timecode. Linear editing systems typically control three or more tape drives and switch video between disc recorders as much as possible. The computer must execute the command precisely, so it must obtain the address of the specified location of the tape at a specific time. Applications can use timecode in a number of ways, mainly the following:

a. Track video and audio sources throughout the editing process

b. Synchronize video and audio.

c. Synchronize multiple devices

d. Use undefined bytes in timecode, called: userbits. This usually contains the date, ascii code or industrial information about the movie etc.

3. Capture time code

Usually, time code is generated by some capture card devices capable of generating time code. For example, an rs-422 requires time code to control peripherals and host communication.

After the time is generated, we need to get the timecode from the video and audio in stream format, which can be accessed later. Then we process the time code through the following two steps:

a. Establish a non-consecutive index of each frame position, and associate the time code with each frame one-to-one. This list is written at the end of the file after capture is complete. The list can be an array of matrices with a structure like the one below, provided here is just DirectShow for brevityA simplification of the TIMECODE_SAMPLE structure.

struct {
DWORD dwOffset; // offset bits in frame
char[11] szTC; // value of timecode in offset value
// hh:mm:ss:ff is a non-drop frame format hh:mm:ss;ff is a drop frame format
For example, here can give a video capture stream in Timecode for:

{0, 02:00:00:02},
{16305, 15:21:13:29} // Time format at frame 16305

Using this table, the timecode of any frame will be calculated just fine.

B. Another way is to write the time code as video and audio data. We do not recommend this kind of use and therefore will not be introduced.

The files written in the timecode can be edited, composited, synchronized, etc. This is written here, enough for us to understand timecode. Many others are about the introduction of the standard, you can refer to it if you are interested.

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You can go to the core to find its data sheet and you will know it at a glance, there are Massive database, chip data is relatively complete, and you can download it for free

⑶ The difference between ETP and ETF. Introduce in detail what is ETP

ETF and ETP are institutional investment It provides convenience and reduces risk for investors and accredited investors to enter the cryptocurrency space. However, ETFs are funds, and ETPs are bonds, so ETFs are subject to stricter supervision.
1.Bitcoin ETF
The full text of ETF is Exchange Traded Funds, that is, trading platform-traded funds. Literally, it is a fund that can be traded on a trading platform. Simply put, it is a basket of targets that track the trend of the broader market. You can think of ETFs as a basket of stocks that are selected based on some index that indicates stock movement, such as the S&P 500, which records the overall movement of the stocks of 500 companies. The basket of stocks in the ETF, then, is the stocks of these 500 companies. The point to make is that you don’t actually own those 500 stocks directly, what you own is a certificate that you own the ETF. The most well-known ETF is the SPY ETF, the world’s largest exchange-traded fund that tracks the overall level of the S&P 500 stock market index.
Bitcoin ETFs are Bitcoin-based ETFs. If you buy a Bitcoin ETF, you are indirectly investing in Bitcoin and owning a tradable Bitcoin fund instead of directly owning Bitcoin. However, if you buy a bitcoin ETF and buy bitcoin directly, there is no difference in return, because the bitcoin ETF tracks the price of bitcoin, and when bitcoin goes up, the ETF goes up, and vice versa. ETFs are just another way of investing in Bitcoin. The only difference is that we no longer have to worry about whether the bitcoin will be stolen, no longer worry about where to store the bitcoin, and no need to go through cumbersome procedures.
2. ETP
The full text of ETP is Exchange Traded Procts, that is, trading platform trading products. ETPs are open-ended investment products listed on trading platforms, priced derivatives, and day-traded and settled on national trading platforms like stocks. It is classified as a senior structured debt security. Basically, they are linked in value to other securities, commodities or indices. ETPs are passive investments designed to replicate the performance of a particular market by tracking an underlying benchmark index, and will outperform active investment products most of the time. The Swiss securities trading platform SIX defines ETPs as follows: ETPs are collateralized, bearer debt securities that do not earn interest and can replicate the underlying asset (usually from commodities) on a basic or leveraged basis. Like ETFs, they are intraday traded in multiple market maker spaces, but legally they are not funds. Take, for example, the first global multi-cryptocurrency ETP launched by the Swiss stock exchange in November 2018. The Amun ETP is based on the Amun Crypto Basket Index, which tracks the performance of the five best cryptocurrencies in terms of market capitalization and liquidity. At the time of listing, the index was composed as follows: BTC (49.7%), XRP (25.4%), ETH (16.7%), LTC (3%) and BCH (5.2%).
A spokesman for Swiss financial regulator Finma said: “It is important to distinguish between ETPs and ETFs, as ETPs are not subject to the Collective Investment Schemes Act (Cisa).” Conceptually, Amun ETPs are to some extent Similar to ETFs above, they both allow institutional and accredited retail investors to invest in digital assets without a custodian and without facing additional regulatory hurdles. However, in order to increase the chances of an ETF being approved by the SEC, companies applying for ETF products must demonstrate that the cryptocurrency futures market is sufficiently stable, which is the reason the SEC has repeatedly denied approval.The rationale for a Bitcoin ETF. For ETPs, there is no such requirement, as there are already ETP products in the United States, such as Bitcoin Investment Trust by Grayscale Investment.

⑷ What is Litecoin, can you introduce it in detail?

Litecoin is a virtual currency similar to Bitcoin, (LTC, currency symbol: Ł) is a network currency based on “peer-to-peer” technology and an open source software project under the MIT/X11 license.

⑸ Seek airtight leak detector innoamtec LTC-101 data introduction

innomatec LTC-101 is the most cost-effective high-precision leak detector in the whole series. If you need the relevant parameter information, you can leave your email and send it to you. Source: [Guangzhou Wanken Machinery]

⑹ Introduction of Litecoin

Litecoin (abbreviation: LTC, currency symbol: Ł) is a network currency based on “peer-to-peer” technology and an open source software project under the MIT/X11 license. It helps users make instant payments to anyone in the world. Litecoin is inspired by Bitcoin (BTC) and technically has the same realization principle, the creation and transfer of Litecoin is based on an open-source cryptographic protocol that is not governed by any central authority. Compared to Litecoin, which was designed to improve Bitcoin, Litecoin has three notable differences. First, the Litecoin network can process a block every 2.5 minutes (instead of 10 minutes), thus providing faster transaction confirmations. Second, the Litecoin network is expected to produce 84 million Litecoins, more than four times the amount issued by the Bitcoin network. Third, Litecoin uses the scrypt encryption algorithm first proposed by Colin Percival in its proof-of-work algorithm, which makes it easier to mine Litecoin on ordinary computers than Bitcoin. Each Litecoin is divided into 100,000,000 smaller units, defined by eight decimal places.

⑺ What does LTC mean

LTC (Leads To Cash), from leads to cash, is a marketing strategy established from a marketing perspective. Set of end-to-end business processes. Huawei is using LTC to promote the improvement of the ability of the entire enterprise marketing field. Xianniu is a practitioner of the LTC idea. Xianniu integrates the logistics, human flow, capital flow and information flow in different links of IT services by opening up the data in the internal and external systems of IT service providers, and uses digital technologies and tools to promote IT Transformation and upgrading of service providers to achieve excellent business operations.

⑻ What is LTC

LTC is shorthand for Litecoin, which is inspired by Bitcoin (BTC) and technically has the same implementation In principle, the creation and transfer of Litecoin is based on an open-source encryption protocol that is not managed by any central authority.

Litecoin LTC market information can be found in Yingwei Finance


⑼ btc/ltc/eth/etc What does it mean

BTC is Bitcoin
LTC is Litecoin
ETH is Ethereum
ETC is Ethereum Classic


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